1. Field of the Invention
This invention relates to a method of manufacturing parts for compressors, and more particularly to a method of manufacturing stationary and moving scroll members for use in a rotary compressor.
2. Description of the Prior Art
Most of scroll members for a rotary compressor have so far been manufactured by casting or by joining a plate material to a belt-shaped scroll which has been formed by an extrusion molding as disclosed in Japanese patent laid-open publication No. 59-208186 or by a plastic working as disclosed in Japanese patent Laid-open publication No. 59-191578.
In case of manufacturing such scroll members by casting, the productivity is low; the percentage of occurrence of unacceptable castings is high, and cutting portions are so much that the stocks cannot be finished by machining at one time, therefore, after effecting rough finishing several times, final finishing work is performed. On the other hand, in case of joining the plate material to the scroll, casting or molding is not suitable for mass production of the scroll members because it requires many steps to manufacture.
Recently, as disclosed in Japanese patent Laid-open publication No. 60-102243, a forging process has been employed to manufacture such scroll members. However, because of complicated shape or configuration of the members, it is difficult to manufacture such products with predetermined dimensions. In case of manufacturing by forging, disc-shaped or pan-cake shaped materials has been used, however, there has been a tendency that products manufactured by materials of such a configuration, i.e., scroll members are thin in wall thickness in the scroll portion.